Fibrocalcific phenotypes in calcific aortic valve disease: imaging characterization, treatment timing, and efficacy assessment.

Calcific aortic valve disease involves two structural processes, fibrous matrix remodeling and mineral deposition, that contribute unequally between patients, so leaflets of similar hemodynamic severity need not share the same tissue composition. Histologic and multi-omics studies have mapped this heterogeneity across sex, age, and valve morphology, and contrast-enhanced computed tomography angiography (CTA) has brought compositional assessment into living patients and into longitudinal follow-up. Calcific burden behaves consistently: it tracks stenosis severity, predicts progression, and carries prognostic weight. Findings for noncalcified tissue are less settled and depend on the population studied and on how the measurement is made. Whether total fibrocalcific volume performs well as a structural endpoint and whether CTA-derived noncalcified tissue volume adds predictive value beyond calcification are consequently two separate questions, and the literature often merges them. Pharmacologic trials in patients have almost always measured calcification progression or hemodynamics rather than longitudinal change in the fibrous matrix. Randomized lipid-lowering and mineral-targeted trials in patients have been negative, whereas animal and cell experiments show that established mineral lesions, cell states, and function can sometimes be modified, although these responses do not necessarily move together. This review integrates histology, multimodality imaging, clinical cohorts, pharmacologic trials, and preclinical intervention studies to define the fibrocalcific phenotype, distinguish prevention from slowing and reversal, and align therapeutic timing with endpoints at the levels of activity, tissue burden, valve function, myocardial response, and clinical events. Longitudinal measurement of leaflet composition and validation of treatment-induced change against functional outcomes remain the central gaps.